A hitting face of a golf club head having improved strength properties. In one embodiment, the hitting face is made from multiple materials. The multiple materials form layers of a laminate construction of a flat portion of a hitting face insert. The layers of the laminate are joined together using a diffusion bonding technique. Preferably, at least one layer of the laminate is a thin layer of a very strong material that forms the rear side of the hitting face insert so as to prevent failure of the hitting face insert on that rear side due to repeated impacts with golf balls.